Process for treating marine oils



Patented July 31, 1945 rnocnss FOR TREATING MABlNE olLs Loren 0. Bnxton, Belleville, N. 1., alsignorto National Oil Products C pany.

1 a corporation of New Jersey No Drawing. Application February 20, ms

Serial No. 431,697

i 2 Claims. This invention relates to the treatment of marine. oils and more particularly to the refining of fat-soluble vitamin-containing marine oils.

Various processes have been proposed for hydrogenating vitamin-containing marine oils toeiiect deodorization and stabilization thereof. In accordance with most of these proposals, the hydrogenation is carried to a point where a very substantial portion of the highly unsaturated fatty acids is partially or completely hydrogenated with a consequent decrease in the iodine value of the oil. In substantially all cases when vitamin-containing oils are treated by such proccases, a portion of the vitamins is destroyed and oftentimes a very substantial amount is lost;

consequently, such processes have not met with any considerable degree of commercial success. Other processes have been proposed wherein the vitamin-containing marine oil is hydrogenated under more mild conditions, so that while some deodorization does take place, the vitamin content of the oil is not deleteriously affected to any great extent. .In most cases these processes of deodorization have been carried out at pres- I sures equal to or greater than atmospheric pressure, and at temperatures usually not above about 70 C. as it was believed that the vitamins would be deleteriously aflected ii the temperamay also be obtained by contacting a fat-soluble vitamin-containing oil with a suitablesolvent at a temperature at which at least the maior portion of the oil is miscible with the solvent and then' cooling the mixture, whereby a solvent layer containing the desired extract separates. Among the solvents whichwere found to be-particularly suitable for use in this latter process are those listed in the table below:

Table I 1. Aliphatic and alicyclic monohydroxy alcohols containing from 3 to 6 carbon atoms. 2. Ehtersot said alcohols with aliphatic mono- ,carboxylic acids, said esters containing not I more than 8 carbon atoms. 3. Aliphatic and alicyclic aldehydes containing not more than 6 carbon atoms. a. y 4. Aliphatic l'atones containing not more than 6 carbon atoms.

It will be noted. that these preferred solvents are all liquid organic compounds having the properties of being miscible with fatty oils attemperatures above room temperature and partially immiscible therewith at temperatures substantially below room temperature; experiments in this connection have shown that solvents 01' this ture was allowed to go much above about 80 C.

fto 90 C; However, marine oils which are so treated oftentimes still. have a fishy taste and odor in addition to containing certain constituents which, although they themselves are not odoriferous or objectionable to any great extent, tend to develop into highly undesirable, obnoxious and odoriferous mai'erlals v..vvhich greatly detifiict from the value'oi the vitamin-containing o It has been found that the treatment of fatsoluble vitamin-containing marine oils with certain types of organic solvents yields valuable highly potent extracts containing a portion of the fat-soluble vitamins along wlth'the bulk of the antioxidants originally'oontained in theoil. Thus tat-soluble. vitamin-containing oils containing at least 2% unsapo'niflable matter may be subjected to extraction with hot methanol ,or

. ethanol and the mass then cooled, whereby an alcoholic layer separates containing dissolved therein; an oil having a much higher vitamin potency than the original oil; this process is more fully described and claimed ininy copending application Serial No. 32l-,409, llled' February 29. 1940, now Patent-No. 2,347,460, datedAprll 26. 1944. -Highly potent tat-soluble vitamin extracts class may be used generally in the process hereinabove described. This process is disclosed and claimed in copending application Serial No.

343,558, filed July 2,1940, in the name of Dombrow.

improved process for the refining oii'at-soluble vitamin-containing marine oils.

A further object of this invention is to provide an'improved process for the. hydrogenation of vitamin-containing marine oils to improve the taste and odor thereof.

Still another object of this invention is to provide improved vitamin-containing marine oils.

Another object of this invention is to provide a process whereby all the valuable constituents of vitamin containing marine oils maybe utilized.

Other objects of the invention will in part be obvious and will in part appear hereinafter.

l have round that the above and other obiects oi the invention may be accomplished by treating a crude or partially refined tat-soluble vitamin-containing marine oil with hydrogen under such conditions that the iodine number of the oil remains substantially unchanged. but that the odoriierousconstituents in the oil are converted It is the object of this invention to provide an to forms in which they are unobiectionable, the conditions also preferably being such that there is a tendency for certain side reactions to take place, particularly the formation of fatty isoacids and glycerides thereof which have a melting point considerably higher than their correspondingv normal fatty acids and glycerides. If de-' sired, the oil may be treated, prior to hydrogenation, by a process similar to the processes of either of the two hereinabove identified applications, but in such a manner that only a proportionately small amount of the vitamin content of the marine oil is removed, but a major portion of the free fatty acids; a large part-of the undesirable components in the oil responsible for the objectionable odor and taste thereof, nit'rogenous compounds such as amines, and various constituents which themselves are not obieceral steps and the relation of one or more of such,

steps with respect to each of the others, and the product possessing the features, properties and the relation of elements, which are exemplified in the following detailed disclosure, and the scope of the invention will be indicated in the claims.

In most cases when vitamin-containing marine oils are hydrogenated to remove the taste and odor therefrom, some of the unsaturated constituents are hydrogenated at the double bonds: but usually under conditions favorable for hydrogenation of double bonds, a certain amount of the vitaminqcontent of the oil is detrimentally affected with a consequentloss of vitamin potency.

1 have found that the majority of the disagree-' able constituents of vitamin-containing fish oils maybe hydrogenated and converted to substantially non-disagreeable substances without materially hydrogenating the unsaturated components of the oil at the double bonds or impairing the genation is carried out at low pressures and at moderate tohigh temperatures, in the presence of a relativtly active catalyst. Furthermore, such hydrogenating conditions are very favorable to vitamin potency of the oil provided the hydrothe formation of-fatty isoacids and glyceridesthereof from their corresponding normal fatty acids and glycerides, particularly if relatively large amounts of catalyst are used It is to be understood that theterm "isoacids" as used herein refers to the trans form of acids in cis-trans advantageous as the isoacids .and their glycerides 05 have melting points somewhat higher than the corresponding cis acids and their glycerides, e. g. elaidic acid has a melting point of about 38 C. higher than that of oleic acid. -Consequently assasos normal acids which have been hydrogenated although the melting points of the acids may not differ greatly. The reason for this is that the solidified isoacids have a crystalline structure which makes them more readily separable from the oil. Therefore, if desired, the hydrogenated oil may be treated to remove an isoacids and glycerides thereof that may have been fonned during the hydrogenation step. Any process suitable for the removal of stearin may bev used to remove the lsoacids and glycerides thereof.

In carrying out the hydrogenation step of the process any suitable pressure under that of atmospheric (1 mm. to 750 mm.) may be resorted to;

however, it'is highly preferred to operate within the range of about one to twenty millimeters. Medium to high temperatures, 1. e. from about C. to about 200 C. may be maintained during the hydrogenating step and the use of an active catalyst, e. g. Raneynickel catalyst is preferred. The conditions which appear to be the most favorable for the Occurrence of side reactions resulting in the formation of isoacids are temperatures of around C. or above; low ressures, preferably below 20 mm.; and relatively large amounts of active catalyst, e. g.5% of Raney nickel catalyst. In general, from 3 to 5 hours are usually sufiicient to completely deodorize the oil;

however, longer or shorter periods of hydrosenation maybe resorted to, if desired.

' In the past it has been the common belief. that when a vitamin oil is treated with hydrogen in the presence of a catalyst at temperatures exceeding 100 0., rapid destruction of the vitamin content results. However, I have found that such is not the case if the hydrogenation is carried out at reduced pressures, and that when a sub- ,atmospheric pressure is maintained, temperatures as hiih as 200 C. may be used, although temperatures of about 100 C.-to C. are preferred. Hydrogenation of vitamin-containing marine oils in accordance with my process will produce oils devoid of fishy taste and odor without any appreciable destruction of either vitamin A or vitamin D.

Catalysts other than Raney nickel may be used as any active catalyst will suffice including, inter alia, platinum, palladium, copper-chromium oxide, and nickel on kieselguhr. Generally from about 0.2% to about 5% of catalyst is a suitable amount to use. Q

. When the oil is treated with a solvent before the hydrogenation, the process which is used is much the same (as the processes disclosed in copending applications Serial No, 321,409 (Patent No. 2,347,460) and Serial No. 343,558; i. e. the oil is contacted 'with a solvent at room temperature or above, the oil-solventmixture is cooled to a temperature considerably below room temperature, e. g. 0 C. or lower, whereby two layers are formed, one being the solvent containing the constituents which it is desired to remove from the marine oil along with part of the vitamin content thereof, and also asmall amount of the oil, and the other layer being the'maion portion of the fish, oil now substantially free of undesirable components.

The principal difference between the solvent treatment step in the present invention and the ,the isoacids and glycerides thereof may be-retwo hereinabove identified inventions is that here moved from the oil in much the same manner as the stearins are removed, with a consequent increase in the vitamin potency of the end product. In factthe isoacids in many cases are more easily usually only one, and seldom more than two, extractions are made. Also, in this process the solvents which are used are as a general rule ones which are somewhat less emcient extractives removed from the oil than are the corresponding '1 of the vitamins than the solvents used in the two preferred to use 91% isopropanol instead of 99% previously mentioned inventions. Thus, for example, in application Serial No. 343,558, when isopropanol is the solvent, it is usually preferred to use 99% isopropanol, whereas in this invention it is preferred to use 91% isopropanol. Although highly potent vitamin extracts may be obtained using 91% isopropanol, the amount of vitamins which is removed with each extraction is much less than when 99% isopropanol is used. However, the 91% isopropanol is more efficient in removing the undesirable components of the vitamin-containing marine oilthan is the 99% isopropanol, and in most cases one extraction with 91% isopropanol will remove the major portion of the objectionable constituents of the oil while removing only a small portion of the vitamin content thereof. However, the'residue which remains when the solvent is removed from the solvent extract, although it is very dark colored and has a disagreeable odor and taste, is of a somewhat higher vitamin potency than the original oil and contains 'most of the natural antioxidants originally present in the oil; consequently it is a valuable product. One of the principal uses to which it is applicable'is for the fortification of and the stabilization towards oxidative changes of vitamin-containing oils used for agricultural purposes, e. g. the enriching of the vitamin content of livestock and poultry feeds where the taste and odor of the feed are not so important as in products for human consumption. Thus b the process of this invention, vitamin-containing oils highly suitable for human consumption are produced, and the by-products of the process are valuable materials suitable for other purposes. Consequently by the use of this process, it is now possible to utilize to the fullest extent andin the most advantageous manner all of the valuable constituents of vitamin-containing marine oils.

In carrying out the solvent extraction of the oil before the hydrogenation, I prefer to use a solvent selected from the group consisting of methanol, ethanol and solvents miscible with fatty oils at temperatures above room temperature and partially immiscible therewith at temperatures substantially below room temperature, particularly those of the type listed in Table I above. Thus in addition to methanol and ethanol, solvents such as n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, n-amyl alcohol, isoamyl alcohol, secondary amyl alcohol, furfuryl alcohol, allyl alcohol, diacetone alcohol, fl-hydroxy ethyl acetate, methyl formate, ethyl formate, ethyl acetate, methyl acetate, isopropyl acetate, glycol diformate, glyool diacetate, methyl levulinate, ethyl levulinate, methyl aceto acetate, ethyl aceto acetate, methyl furoate, vinyl acetate, furfural, propionaldehyde, crotonaldehyde, acetone, methyl ethyl ketone, acetonyl acetone and propylene chlorhydrin 'may be used. I have found that methanol and ethanol may be most effectively used with oils containing more than 2% unsaponifiable matter; the remaining solvents may be employed with advantage with practically any vitamin-containing fatty oil, isopropanol being particularly useful b reason of its efficiency, cheapness and ready availability. Mixtures of the above solvents may also be used, if desired. In case the solvent which is being used is a quite efficient extractive for vitamins A and D, it is preferred to dilute it with water or some other non-extracting liquid miscible with the solvent so as to reduce the amount of vitamins extracted and leave the major portion of the vitamins in the treated oils. For example, it is isopropanol as has been mentioned hereinabove.

In treating the vitamin-containing marine oil with the solvent, the relative proportion of solvent to oil may vary widely; preferably the ratio of solvent to oil should be greater than one and inmost cases mixtures containing between about 2% and about 25% oil are suitable. The oil and solvent are mixed, and if desired, the mixture is heated until the oil or the-greater part thereof is dissolved in the solvent. In using ethanol and methanol, which are-two of the preferred solvents for extracting the oil prior to the hydrogenation, the solvent and oil will not become completely miscible even when heated to temperatures considerably above room temperature, but it is not necessary that they become completely miscible as the solvent will selectively extract the constituent which it is desired to remove.

.After the oil has been thoroughly contacted with the solvent was to extract the constituents which it is desired to remove, the mixture may be permitted to cool so as to efiect a separation of the materials into two layers. The temperature to which the solution is cooled may vary from about room temperature to as low as -70 C. or lower. I have found, however, that it is pref- .erablev to cool the solution with slight agitation to temperatures somewhat below about 0 C., e. g. in the neighborhood of -18 C. One layer consists chiefly of the portion of the original oil insoluble in the solvent at low temperatures. vitamin content of this fraction is usually slightly less than that of the original oil. The solvent layer will contain the-majority of the undesirable materials which it is desired to remove from the oil along with a small per cent of the vitamins in the oil and the majority of the natural antioxidants of the oil. The residue remaining after removal of the solvent from the solvent fraction may be utilized as described hereinabove or for other purposes for which it may be adapted.'

The treated oil which will now be substantially free of undesirable components and substantially lighter than the original oil but possessing a slight fishy taste and odor is partially hydrogenated as a light colored, bland, odorless product contain- .ing the major portion of the vitamins present in the original oil. This embodiment of the invention, i. e. solvent extraction of the oil followed by partial hydrogenation, forms my preferred process; however, it is to be understood that in many cases a preliminary solvent extraction step is unnecessary, and that completely bland, odorless products may be obtained merely by partially hydrogenating the vitamin-containing fish-oil in accordance with this process.

The refined oil prepared by the process of this invention may be used as such or it may be saponi fied in the usual manner to produce vitamin concentrates substantially free of obnoxious tastes and odors, or it may be-treated further in accordance with the process of either application Serial No. 321,409 or 343,558 to produce extracts having a vitamin potency far in excess of that of the original oil. When any appreciable quantities of isoacids are formedduring the hydrogenation, it is particularly desirable that they be removed as by their removal the potency of the oil will, of course, be increased. Furthermore,

' any odors acquired during hydrogenation may be The.

25parts of shark liver'oil containing 100,000

v'er oil;'-ftu'na liver liver oil, solef1iver oil, spear-fish" liver oil, sword fish liver'oil, whale liver 'c il. sardinef oi l.

herri'ng'oiLetcI- This process of "partialhydrogenatio'n is' partures or temperatures slightly above room tem perature with' afsolvent selected from thegroup" consisting of methanoL-ethanol, n-propanol, iso- *propanol, methyl acetate,-ethyl=acetate; methyl ethyl ketone, acetone and diacetone'alcohol. the

last sevennamed solvents containing atleast te For a fuller understanding of the nature 13nd objects of the' invention; reference should be had to the following examples which ar'e given merely to further illustrate the invention and are not to be construed in a limiting sense, all parts'given being byweight. l

. H I Bramble-I parts of shark iliver 'oil containing 100,000 units of vitamin A/gm. having a fishy taste-and odor were mixed with 0.25 part of Raney nickel catalyst and the mixture completely deaerated.

Thesame was treated-with a steady supplyof hydrogen at 180 C. for one hour under a pressure of 8 mm. The treated oil was" slightly lighter" in color than the original oiland completely devoid of tasteand odor, and the vitamin potency'was the same as thator-the untreated oil.

Exampl e II 25 parts of shark liver oil containing-60,000

units vitamin A/gm. having a' fishy taste and odor were mixed with 0.5 part of activated-platinum oxide catalyst .and the mixture deaerated and then heated at 98 C. under a pressure of 10 mm. fortwo :hours in the presence of hydrogen gas. The mixture was cooled and the catalyst removed. The oil was odorless, completely 'devoid of .anyfishy'taste, and; the vitamin potency was unchanged.

' Example -III 500'parts of crude shark liver oil containing l00,000 units vitaminA/gm. were mixed with 10 parts of Raney-nickel catalyst and heated at 100 C. for six hours under a pressure of 10 to 15 mm. in the presence of hydrogen gas. 'I'hetreated oil was free of fishy tastes and'odors and slightly lighter in 'color than the original oil, and the vitamin potency'was the same as before treat M ing. oncooling the oil, a crystalline-like material which resembled ela'idic acid (isooleic" acid) separated from the solution. The cloud and pour point of the oil was appreciably higher than that g of the original oil.

. Example units of vitamin A/gm. having a fishy taste and odor were mixed with 1 part of Raney nickel catalyst'and the mixture heated at 100 C. for

minutes under a pressure of 10 mm. in an inert atmosphere to deaerate the oil and free it from peroxides, etc. Hydrogen gas was then passed asefbjie J isoacids.

through the oil under the, same conditions for 5 hour he f 'catalyst' was removed by filtering. 'li 'hejtratedoil'was completely devoid of odor and ftaste. Although the" iodine value was practically unchanged, thepour polnt of the .oil. had increased considerably because of the formation of J r mag a Ancrude shark liver oil containing 103,000 units .;of vitamin A/gm. was extracted twice with isoapropanol by contactingrthe oil with the isopro- -panol, coolingthemixture to a temperature of about -18 C. and separating the solventlayer zirom the 'oilimmiscible therein. 50 parts of' the oil; immiscible .with. the solventxatthe low temperature,- which" contained :97,000='units of vitamin ;-.A/gm.- were mixed; withvil part-of Raney nickel catalystand the mixture heated at 150 C. under apressure of 15mm: in thepresence of hydrogen for 0118110111- u-The mixture was cooled and filtered to remove-the catalyst. The resulting-product which contained 'the :major portion of-thevitamins present in .the original oil, was a bland-tasting. oil completelydevoid of fishiness.

ridmpz e'vrf g V 200'. parts oftuna liveroil containing 67,000

. units of vitamin -A/sm. and 20,000,,units of vita- I were treated further essentially as described in min .l D/gm. were extracted. three times'with methanol bycontacting the oil with the methanol at about50? C., coolingthymixtureto about 18 C. and separating the supernatant solvent layer from-the immiscible oillayer. 50 parts of the oil ,immissible with. the solvent at. the low temperature and-possessing a fishy taste and odor Example V. The resulting oil which contained the majorportion of the vitaminA and D contentpresent in the orlginaloil was free from fishiness and was light in color.

'Emample VII parts of the immiscible oil resulting after extracting crude halibut liver oil twice with 91% isopropanol at -18 C 'and which possessed a fishy taste and odor were mixed with .3 parts of a nickel catalyst on aluminumo'xide, and the mixture heated to C. for 5minutes under a pressure of 5 mm..in the presenceof N gas to deaerate the ,oil.v Hydrogen gas was then passed through the oil-catalyst mixture under the same temperature-and pressure conditionsfor 20 minutes. The mixture .was thencooled to .room temperature and filtered to remove'the catalyst. The

resulting oil was completely devoid of fishiness and contained the major portion of, the vitamins present in the original oil.

It will be evident from the above description ,and examples ,that' this invention provides an efficient processji'cr.thelutilization in the most advantageous manner vof'all of the valuable, constituents in yitamin-containinglflsh oils.

Since certain changesv maybe 'madein carrying out the above process withoutdeparting from the scope of the invention, it is intended that all matter contained in the above description shall be interpreted as illustrative and not in a limiting sense.

Having described my invention, what. I claim as new and desire to'secure by Letters Patent, is:

lLArprocess of refining a vitamin-containing oilandimproving the taste and odor thereof, which comprises contacting a fat-soluble vitamincontaining marine oil with hydrogen in the presence of an active hydrogenation catalyst at a temperature between about 90 C..and 200 C. under a pressure of about 1 to 20 mm. for a perind of time insuflicient to affect the iodine value thereof.

2. A process of refining a vitamin-containing oil and improving the taste and odor thereof, which comprises'contactinga fat-soluble vita.-

min-containing marine oil with hydrogen in the presence of an active hydrogenation catalyst at a temperature between about 100 C. and 170 C. under a pressure of about 1 to 20 mm. for a period of time insumcient to affect the iodine value thereof.

LORAN O. BUX'ION. 

